Steffen Strassburger

Future trends in distributed simulation and distributed virtual environments: results of a peer study

This paper reports main results of a peer study on future trends in distributed simulation and distributed virtual environments (Strassburger et al. 2008). The peer study was based on the opinions of more than 60 experts which were collected by means of a survey and personal interviews. The survey collected opinions concerning the current state-of-the-art, relevance, and research challenges that must be addressed to advance and strengthen these technologies to a level where they are ready to be applied in day-to-day business in industry. Most important result of this study is the observation that as research areas, both distributed simulation and distributed virtual environments are attributed a high future practical relevance and a high economic potential. At the same time the study shows that the current adoption of these technologies in the industrial sector is rather low. The study analyses reasons for this observation and identifies open research challenges.

Migration of HLA into Civil Domains: Solutions and Prototypes for Transportation Applications

The United States Department of Defenses (DoD) High Level Architecture for Modeling and Simulation (HLA) is a mandatory stan dard for military simulations. The situation in the civil simulation community is differ ent : simulator interoperability is desirable and even required, but there is no driving force to mandate the use of a certain standard. This article addresses the problems that a simulator interoperability standard in the civil world faces and discusses how HLA can possibly become the standard that is needed. Several solutions for connecting civil simula tion tools using HLA are introduced and some prototypical applications focusing on the area of transportation are demonstrated.

Distributed simulation and industry: potentials and pitfalls

We present the views of five researchers and practitioners of distributed simulation. Collectively we attempt to address what the implications of distributed simulation are for industry. It is hoped that the views contained herein, and the presentations made by the panelists at the 2002 Winter Simulation Conference will raise awareness and stimulate further discussion on the application of distributed simulation methods and technology in an area that is yet to benefit from the arguable economic benefits that this technique promises.

Initialization of simulation models using CMSD

In the context of online- and symbiotic simulation, the precise initialization of simulation models based on the state of the physical system is a fundamental requirement. In these simulations, the simulation model typically serves as an operational decision support tool. Obviously, it can therefore not start empty and idle. The accurate capturing of initial conditions is fundamental for the quality of the model based predictions. In literature, it is only generally stated that the simulation model must maintain a close connection with the physical system. Our work systematically investigates which data from the physical system is needed for initialization, how it shall be transferred into the simulation model in a standardized way, and which potential problems must be solved in the simulation system to adequately initialize its model elements. We present a solution based on the core manufacturing simulation data (CMSD) standard, suggest necessary extensions and demonstrate a prototypical implementation.

Scalability in distributed simulations of agent-based models

Research on systems of autonomous agents, called multiagent systems (MAS), has received much interest in the domain of (distributed) artificial intelligence in recent years. MAS are most suitable for the development of distributed applications within an uncertain and dynamically changing environment (Logan 2005). For validation of such systems agent based simulation is a new modeling paradigm not limited to systems which qualify as MAS by default. The focus of the work presented here is on scalability aspects of simulation environments for agent based simulations. Scalable solutions are required, as complex models require the capability to simulate hundreds or more complex deliberative agents. This is a capability which is often lacking in existing simulation environments for agents. We investigate different aspects which influence scalability and present a solution for enabling a scalable and efficient distributed simulation of agent-based models based on an adapted optimistic synchronization protocol which limits the level of optimism by using knowledge about agent interaction patterns.

Commercial-off-the-shelf simulation package interoperability: issues and futures

Commercial-Off-The-Shelf Simulation Packages (CSPs) are widely used in industry to simulate discrete-event models. Interoperability of CSPs requires the use of distributed simulation techniques. Literature presents us with many examples of achieving CSP interoperability using bespoke solutions. However, for the wider adoption of CSP-based distributed simulation it is essential that, first and foremost, a standard for CSP interoperability be created, and secondly, these standards are adhered to by the CSP vendors. This advanced tutorial is on an emerging standard relating to CSP interoperability. It gives an overview of this standard and presents case studies that implement some of the proposed standards. Furthermore, interoperability is discussed in relation to large and complex models developed using CSPs that require large amount of computing resources. It is hoped that this tutorial will inform the simulation community of the issues associated with CSP interoperability, the importance of these standards and its future.

Distributed computing and modeling & simulation: speeding up simulations and creating large models

Distributed computing has many opportunities for Modeling and Simulation (M&S). Grid computing approaches have been developed that can use multiple computers to reduce the processing time of an application. In terms of M&S this means simulations can be run very quickly by distributing individual runs over locally or remotely available computing resources. Distributed simulation techniques allow us to link together models over a network enabling the creation of large models and/or models that could not be developed due to data sharing or model reuse problems. Using real-world examples, this advanced tutorial discusses how both approaches can be used to benefit M&S researchers and practitioners alike.

The road to COTS-interoperability: from generic HLA-interfaces towards plug-and-play capabilities

Interoperability between commercial-off-the-shelf (COTS) simulation packages (CSPs) is a topic which has been discussed for many years without a solution. With the advent of the high level architecture for modeling and simulation (HLA) for the first time a real industry standard has been made available which promises interoperability for a wide range of simulation systems and applications. Successful attempts to integrate HLA interfaces into different simulation packages have been made in the past. However, these interfaces typically place a significant overhead on the simulation developer. Also, as often a generic HLA interface is provided, different HLA interfaces for different simulation packages are not necessarily interoperable per se, as there are different possible ways to use HLA for the same task. This article addresses these issues and discusses interoperability solutions based on and beyond of HLA. It further investigates and comments the interoperability reference solutions put forward by SISOs COTS simulation package interoperability product development group

Temporally parallel coupling of discrete simulation systems with virtual reality systems

The coupling of commercial discrete simulation systems with virtual reality (VR) systems opens new possibilities for the temporal interplay of product and process design. Among the possibilities is establishing virtual training centers aimed at shortening product ramp-up times. Up to now, coupling has only been employed sporadically because of the need to preserve the autonomy of the tools used. This paper focuses on the problems of synchronization as one of the important basic tasks when coupling discrete simulation and VR systems. Existing techniques of synchronization are examined for their suitability for coupling and a method of synchronization based on self-adapting buffer sizes is described.

The SISO CSPI PDG standard for commercial off-the-shelf simulation package interoperability reference models

For many years discrete-event simulation has been used to analyze production and logistics problems in manufacturing and defense. Commercial-off-the-shelf simulation packages (CSPs), visual interactive modelling environments such as Arena, Anylogic, Flexsim, Simul8, Witness, etc., support the development, experimentation and visualization of simulation models. There have been various attempts to create distributed simulations with these CSPs and their tools, some with the high level architecture (HLA). These are complex and it is quite difficult to assess how a set of models/CSP are actually interoperating. As the first in a series of standards aimed at standardizing how the HLA is used to support CSP distributed simulations, the Simulation Interoperability Standards Organizations (SISO) CSP Interoperability Product Development Group (CSPI PDG) has developed and standardized a set of interoperability reference models (IRM) that are intended to clearly identify the interoperability capabilities of CSP distributed simulations.